Opportunities of magnetic resonance imaging in diagnosis of microstructural changes of articular cartilage in osteoarthritis

Aim. To estimate the opportunities of proton density-weighed magnetic resonance tomograms in diagnosis of microstructural changes of articular cartilage (AC) in osteoarthritis (OA) on the basis of proton density (PD) variability analyzed. Materials and methods. Sixty two patients with OA and 8 volunteers without OA were examined. All the patients underwent MRI of the knee joints, using tomograph with magnetic field intensity equal to 1.5 tesla. To assess MR images, semiquantitative measurements of articular tissues on the basis of WORMS protocols were used. To estimate the proton density, manual segmentation of PDFS-weighed images of the knee joint medial condyle was implemented. The proton density was estimated, applying 3-D histogram (0–255). Results. At stage I of osteoarthritis, fall in density H+ in the peripheral zone of AC was observed, but it was preserved in the contact part, exposed to maximum statodynamic loadings. At stage II, significant progressing decrease in H+ density peaks in the AC regions, subjected to lesser loads, with preservation of high spectral peaks in the region of elevated friction was stated. Stage III of gonarthrosis was characterized by decrease in H+-spectra as a whole, especially in the loading regions of AC. At stage IV of OA, global reduction in PD intensity was observed along the whole cartilaginous plate surface. Conclusions. The detected patterns of changes in proton density spectra reflect the known degenerative process in AC with osteoarthritis. This property of proton-weight MR-images can be used for assessment of microstructural changes in the articular cartilage with OA.